In recent years, micro-analytical systems are used to carry out an inspection/analysis of trace substances such as proteins and nucleic acids (e.g., DNA) accurately and at high speed in the scientific field such as biochemistry and analytical chemistry or in the medical field.
As an example of the micro-analytical system, there is a system which fills a channel formed on a micro-channel chip with a buffer solution, injects a sample through an injection port connected to the channel, applies a voltage to both ends of the channel and electrophoreses the sample to conduct an analysis.
The micro-channel chip is manufactured by joining a film (thin film) or thin plate to a chip body in which the channel is formed. A reservoir into which a liquid is injected is formed at both ends of the channel, and an electrode is formed in each reservoir. As an example of an electrode forming method, a method in which an electrode pattern is printed on a film or thin plate with a carbon ink is known (see PTL 1). One end of the electrode pattern formed in this manner is formed so as to be located inside the reservoir and the other end thereof is formed so as to be located outside the reservoir. The micro-channel chip is configured so that the electrode of the electrophoresis apparatus is made to contact the other end of the electrode pattern and a voltage can be applied to the liquid sample without contacting the liquid sample injected into the reservoir.